The present invention relates to integrating subscriber management and call control functionalities in a packet data network. More particularly, the present invention relates to integrating the functionality of a network access server and a call session server in a wireless packet data communication system.
Wireless communication systems and networks are used in connection with many applications, including, for example, satellite communications systems, WiFi access systems, cellular communication systems, and with user equipment such as portable digital assistants (PDAs), laptop computers, Treos, Blackberries, and cellular telephones. One significant benefit that users of such applications obtain is the ability to connect to a network (e.g., the Internet) as long as the user is within range of such a wireless communication system.
Current wireless communication systems use either, or a combination of, circuit switching and packet switching in order to provide mobile data services to a mobile subscriber. Generally speaking, with circuit-based approaches, wireless data is carried by a dedicated (and uninterrupted) connection between the sender and recipient of data using a physical switching path. Once the direct connection is set-up, it is maintained for as long as the sender and receiver have data to exchange. The establishment of such a direct and dedicated switching path results in a fixed share of network resources being tied up until the connection is closed. When the physical connection between the sender and the receiver is no longer desired, it is torn-down and the network resources are allocated to other users as necessary.
In general, a data flow in packet-based approaches is “packetized,” where the data is divided into separate segments of information, and each segment receives “header” information that may provide, for example, source information, destination information, information regarding the number of bits in the packet, priority information, and security information. The packets are then routed to a destination independently based on the header information. The data flow may include a number of packets or a single packet.
In a wireless communication system, the system typically includes a wired portion and a wireless portion, with the wireless portion being between the user equipment and an antenna. The antenna usually connects to devices that convert data on the wires to radio signals, other devices that route data to one or more antennas, and/or devices that provide data content to the user equipment such as web pages, email, music, or video. When certain types of multimedia content are desired by user equipment, session initiation protocol (SIP) is used to setup a user session. SIP user sessions support multimedia content such as video, voice, instant messaging, presence, online games, and virtual reality. Typically, SIP is handled by a SIP proxy server, which initiates, modifies, and terminates these user sessions. These SIP proxy servers are separate from network access servers (NAS) that provide subscriber management services. Given the independent nature of the SIP proxy servers and network access servers on a communication network, security problems can arise in the communication between these independent devices and problems can occur with the allocation of network resources.